Regulating transformer



Nov. 10, 1936. A M, UN ER 2,060,477

REGULATING TRANSFORMER Filed Jan. 2, 1935 A. C. Power Load Source /0 INVENTOR A. WWW. c g

$atehie Nov. 10, i 'g iiitiiiifi attain REGULA'HNG TRANSFORMER Arthur M. Unger, Wilkinsburg, Pa, assigncr to Westinghouse Electric 8; Manufacturing Company, East Pittsburgh, Pa", a corporation of lPennsylvania Application January 2, 1935, Serial No. 5%

3 Claims. (01. 171-119) My invention relates to electrical transformers and it has particular relation to improvements in the construction of regdlatingftransformers of the adjustable impedance type.

One object of my invention is to provide a form of construction for such transformers which shall be simple and efiective in-operation and economical to manufacture.

5 Another object is to so construct'the transformer that the output may be efficiently adjusted throughout a wide range without altering 1 the physical relation of the transformer parts.

A further object is to provide means whereby avariation in the effective magnetic coupling between the primary and secondary windings of the transformer is utilized to accomplish such adjustment.

A still further object is to utilize a saturable magnetic leakage path in the transformer core structure for thepurpose of effecting the named variation.

My invention itself, together with additional objects and advantages thereof, will best be understood through the following description of a specific embodiment when considered in conjunction with the accompanying drawing, in

which:

Figure l is a view partially in section showing a transformer constructed in accordance with a preferred embodiment of my invention; and

Fig. 2 is a simplified top or plan view of the transformer of Fig. 1 additionally showing the windings thereof connected in appropriate electrical circuits.

Referring to the drawing, the transformer there illustrated. comprises a magnetic core structure It! having three separate legs, represented in Fig.1 as vertically extending between two spaced horizontally extending members. One of the outer legs of this structure carries a primary winding 'P, while the central leg similarly carries a saturation-control winding C. Surrounding these two windings and the core legs with which they are respectively associated is a secondary winding S.

As shown in Fig; 2, the primary winding may be connected with an alternating-current power source designated by conductors 12 which supplies through the transformer an energizing current to a load circuit 14 which is connected with the secondary winding S. The saturation control winding C may be supplied from any suitable source, such as a battery 16, with a unidirectional energizing current, the intensity of which may be adjusted by manipulating arheostat l8 or other suitable current controlling device.

In operation, the primary winding P circulates flux through the outer core leg which it im- 5 mediately surrounds and a return path comprising the remaining two legs of vthe core structure in parallel. These paths of flux flow are indicated by the arrows in Fig. 1. The secondary winding S has induced in it a voltage determined by the primary winding flux passing through the right hand outer core leg only, that flowing through the central core leg not linking this secondary winding in its return to the lefthand core leg which the primary winding immediately surrounds. Consequently, the effective coupling between the primary and secondary windings may be increased by causing more of the primary flux to flow through the outer leg of the core structure and may be decreased by allowing a major portion of the flux to flow through the shorter and more direct path comprising the central core leg.

This adjustment is preferably efiected by varying the energization of the saturation control 25 winding 0. When this winding is -unenergized, a major portion of the primary flux will flow through the central leg since the reluctance of the return path comprised by it is less than that of the parallel path comprised by the right-hand outer core leg. For this condition minimum voltage will be induced in the secondary winding and the transformer will have its highest impedance and lowest output.

As current is supplied to winding C, the resulting fiowof uni-directional flux' through the central core leg raises its effective reluctance and thereby causes a greater portion of the primary winding flux of the transformer to flow through the parallel branch of the return path comprising the outer core leg. This increase in linkage with the secondary winding raises the voltage induced therein, and thereby lowers the transformer impedance and raises the output. Consequently when the energizing current supplied to winding C is adjusted to its maximum value corresponding to a high degree of saturation of the central leg, the major portion of. the primary fluxwill be shunted through the outer leg and the effective coupling between the primary and secondary windings will be maximum.

It will thus be apparent that the illustrated transformer is capable of a very wide range of effective impedance control in response to changes in the adjustment of the rheostat H.155

This adjustment may either be made manually or caused to be effected automatically in response to changes in a quantity or circuit characteristic which it is desired to maintain constant.

My improved construction is, therefore, one of prior art and by the scope of the appended claims.

I claim as my invention:

1. In a transformer, the combination of a magnetic core structure having three legs, a primary winding carried by one of the two outer legs of said structure, a saturation-control winding carried by the central leg, and a secondary winding surrounding said primary and saturation-control windings andrthe two core legs by which they are carried.

2. An adjustable impedance transformer comprising a magnetic core structure having three legs, a primary winding carried by one of the two 3. An adjustable impedance transformer com prising a magnetic core structure having three legs, a primary winding carried by one of the two outer legs of. said structure for the purpose of circul'ating flux through it and a return path comprising the remaining two legs in parallel, a saturation-control winding carried by the central leg of the core structure for the purpose of adjusting flux flow therethrough by varying the magnetic reluctance thereof, and a secondary winding surrounding said primary and saturation-control windings in a manner to be linked with a portion of the primary winding flux determined by the relative reluctances of the central core leg and the outer core leg upon which no winding is carried.

ARTHUR M. UNGER. 

